Parsnips need the chill of winter for optimum flavor.

Parsnip is considered a winter vegetable because its flavor is not fully developed until the roots have been exposed to near-freezing temperatures for 2 to 4 weeks in the fall and early winter. The starch in the parsnip root changes into sugar, resulting in a strong, sweet, unique taste.

Growing Parsnip

When to Plant

Plant seed in early April or May in deep, fertile soil that is well prepared. Because parsnip seed is very short-lived, you must obtain a fresh supply each spring.

Spacing & Depth

• Plant seeds 1/2 to 3/4 inch deep.
• Because germination of even the freshest parsnip seed is often mediocre, seed thickly, at least two or three seeds per inch to ensure a good stand.
• Space rows 18 to 24 inches apart or plants 8 to 10 inches apart in a bed.
• Parsnip seed is slow to germinate and some gardeners drop a radish seed every foot in the furrow to mark the row and help break the soil crust.
• Once parsnip seedlings are up and growing, pull the radishes and thin parsnip seedlings 2 to 4 inches apart.

Care

Keep young parsnip plants free of weeds by shallow hoeing or cultivation. Watch for swallowtail-butterfly caterpillars, which feed on most members of the carrot family. Handpicking the caterpillars from the leaves normally gives adequate control. If the plants are large and healthy, they can often tolerate swallowtail caterpillar damage. Water thoroughly once a week in periods of extended dry weather to keep growth from slowing in summer.

Common Problems

Low soil fertility is a common problem. However, in well-maintained garden soils adequately supplied with organic matter and fertilizer, this ordinarily should not be a problem. If plants begin to look light green or stunted during the season due to low fertility, the problem usually can be overcome by side-dressing with a complete fertilizer in late June. Avoid fertilizing with fresh clumps of organic matter where parsnips will be grown. This can cause misshapen or forked roots. Parsnips are relatively free of both insects and diseases.

Harvesting Parsnip

Dig the roots (usually 1 1/2 to 2 inches in diameter and 8 to 12 inches long) with a shovel, tilling spade, or spading fork. Yields frequently exceed one pound per foot of row (single roots may weigh more than one pound each).

Selection and Storage

Choose parsnips that are firm and dry without pits. Smaller ones may be more flavorful and tender. Treat parsnips as you would a carrot.

• If the parsnip is large, you must remove its woody core by digging it out with the end of a vegetable peeler or sharp spoon.
• Choose root vegetables that are crisp and firm (not easily bendable).
• Though parsnips look like white carrots, their flavor is slightly stronger, and they taste like turnips or rutabagas.
• The whiter the flesh, the sweeter the parsnip.
• Avoid parsnips that are yellowing or going brown around the core or are older and less sweet.

Gently remove soil and greens.  Store parsnips unwashed in a perforated plastic bag.  Refrigerate in the produce drawer for up to 2-3 weeks or on the countertop for 1-2 days. 

Questions and Answers About Parsnip

Q. Do parsnip seeds germinate poorly?

A. Parsnip seeds germinate very slowly even under the best conditions. The seeds also lose their ability to germinate after the first year, so discard unused seeds. Sowing a few radish seeds with parsnip seeds provides early plants to mark the parsnip row so you can cultivate before the slow-germinating parsnip plants appear.

Q. Can parsnips be left in the soil over winter?

A. If you leave parsnips in the soil over winter, throw a few inches of soil or straw mulch over the crowns after the first fall frosts. A low tunnel could also be used to keep snow off the plants for winter and early spring harvesting. Stored starches are changed to sugar in early spring as the old plants prepare for new growth, thus roots harvested in early spring are especially tender and sweet. The roots lose flavor and become fibrous if you do not harvest them before new tops and seed stalks begin to grow.

Q. Are parsnips poisonous?

A. Cultivated parsnips (Pastenica sativa) are not poisonous at any time during the first growing season nor after the roots have been left in the soil over winter. Some people have reported minor skin reactions when coming in contact with the plant vegetation. Wearing long-sleeved shirts can limit skin contact when working with parsnips.

The wild parsnip is the wild form of cultivated parsnip as both are considered the species Pastenica sativa. Wild parsnip grows throughout Illinois along ditches and on weedy, disturbed sites. Wild parsnip does have toxic properties and the plant’s sap causes severe skin reactions when exposed to sunlight.